Cable splice enclosure

ABSTRACT

A stiff resilient segmented polymeric plastic sheet useful for forming an enclosure about a cable splice or termination. The sheet is grooved to reduce its thickness along narrow linear intersecting latticed strips which define rectangular and triangular patterns in the sheet. The sheet can be easily cut and folded along the narrow strips to form hollow enclosures of various sizes and shapes.

United States Patent 1191 Filreis et al.

[ CABLE SPLICE ENCLOSURE [76] Inventors: Manuel Filreis; Aelred D.Driscoll,

both of 3M Center, Saint Paul. Minn. 55101 [22 Filed: Apr. 10, 1974 2| 1App]. No.: 459,615

Related US. Application Data [62] Division of Ser. No. 228,031. Feb. 22.1972,

abandoned.

[52] [1.8. CI. 174/76; 174/92; 174/138 F; 161/123; 264/272 [5 1] Int. Cl02g 15/08 [58] Field of Search 174/76, 88 R, 91-93. 174/138 F; 161/123.117; 264/272; 156/49,

[56] References Cited UNITED STATES PATENTS 3.187.090 Edwards 174/92 XApr. 22, 1975 ll/l97l Smith 174/76 X 12/1973 Thompson et al: 174/93Primary Examiner-Darrell L. Clay Attorney. Agenl, or Firm-Alexander,Sell, Steldt & DeLaHunt l ABSTRACT A stiff resilient segmented polymericplastic sheet useful for forming an enclosure about a cable splice ortermination. The sheet is grooved to reduce its thickness along narrowlinear intersecting latticed strips which define rectangular andtriangular patterns in the sheet. The sheet can be easily cut and foldedalong the narrow strips to form hollow enclosures of various sizes andshapes.

6 Claims, 9 Drawing Figures CABLE SPLICE ENCLOSURE This application is adivision of application Ser. No. 228.03! filed Feb. 22. I972. nowabandoned.

FIELD OF THE INVENTION This invention relates generally tothe splicingand terminating of electric cables. and in one important aspect toclosures formed around a splice or termination in a communication orpower cable. The invention includes a novel sheet material for forming aprotective enclosure or mold about a splice or cable termination. amethod of applying the sheet material. and the novel enclosures preparedthereby.

DESCRIPTION OF THE PRIOR ART A splice or termination in a power orcommunication cable is conventionally protected by the use of anenclosure which forms a mold for an insulating self-curing resinouscomposition applied in liquid form around the splice or termination.Prior art configurations for molds for this purpose include thepreformed rigid molds of the type shown in U.S. Pat. Nos. 2.862.042 and2.908.744. These molds have a desirable rigidity so that they willmaintain their shape prior to curing of the resinous composition.However. the fixed diameter and length of an individual mold accordingto one of these patents requires that a large variety of sizes of suchmolds must be stocked and accessible to workmen to ensure theavailability of a mold suitable for any splice or termination which maybe encountered. An individual mold of the type described in U.S. Pat.Nos. 2.967.795 and 3.4l9.669 provides better adaptability to the sizesof splices or terminations encountered by workmen. However. use of themold of U.S. Pat. No. 2.967.795 requires careful and extensive handlabor. and the flexibility ota mold according to either of these patentsmay allow undesirable uneven distribution of the insulating resinouscomposition around the splice or termination if proper external supportis not provided prior to the curing of the insulating resin.

SUMMARY OF THE INVENTION The present invention provides a number ofimprovements over these prior art structures and procedures. There isprovided a stiff resilient polymeric plastic sheet having grooves on atleast one surface forming several intersecting latticed sets of spacedparallel linear narrow strips of reduced sheet thickness which definerectangular and triangular patterns in the sheet. The sheet may beeasily severed along the strips of reduced sheet thickness to form asheet section of a desired size and shape. The sheet section can beshaped to form a closure or mold about a cable termination or splice bydeforming the sheet along certain of the strips of reduced thickness.and by fastening the sheet section to itself and to a cable as by tape.The closure itself may provide protection for the termination or splice.or may serve as a mold to shape insulating self-curing resinouscompositions applied in liquid form about the splice or termination.Access to a single sheet according to the present invention allows theworkman to form an enclosure around virtually any normally encounteredsplice or termination. The rectangular and triangular patterns in thesheet afford versatility in the size and shape of a mold substantiallyequal that of the mold disclosed in U.S. Pat. No. 2.967.795. while anenclosure formed from a sheet according to the present invention has arigidity approximating that of the plastic closures of U.S. Pat. Nos.2.908.744 and 2.862.042. and may be used to mold pressure injectedinsulating resin with proper external tape reinforcing.

BRIEF DESCRIPTION OF THE DRAWING The invention may be more readilyunderstood by reference to the drawing in which:

FIG. I is a fragmentary view of a sheet for forming a protectiveenclosure according to the present invention;

FIG. 2 is an enlarged fragmentary cross sectional view takenapproximately along the lines 22 of FIG. 1:

FIG. 3 illustrates a sheet section for use as an enclosure which hasbeen severed from a sheet according to the present invention and ispartially formed around a cable splice;

FIG. 4 is a horizontal plan view. partially in section. of the sheetsection illustrated in FIG. 3 shaped as an enclosure about the cablesplice. with one end of the enclosure taped to the cable;

FIG. 5 is a side elevational view partially in section. of an enclosureformed from a sheet according to the present invention and positionedaround a pair of vertically extending spliced cables to form an openended mold for a self-curing insulating resinous composition around thesplice;

FIG. 6 is a side elevational view partially in section. of an enclosureformed from a sheet according to the present invention and positionedaround a vertically extending communication cable to form an open endedmold for a self-curing resinous composition sealing the termination ofthe cable sheath;

FIG. 7 is a cross sectional view taken approximately along the lines 77of FIG. 4;

FIG. 8 is a cross sectional view taken approximately along the lines 8-8of FIG. 5; and

FIG. 9 is a cross sectional view taken approximately along the lines 9-9of FIG. 6.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIGS. 4, 5 and6 there are illustrated a series of enclosures l0, l2 and I4 formed froma sheet 16 (FIG. 1) according to the present invention. and which haveserved as molds to shape an insulating self-curing epoxy or polyurethaneresinous composition applied as a liquid about the cables. The enclosure10 of FIG. 4 is formed about a running splice I7 in a communicationcable 18. while the enclosure 12 of FIG. 5 is formed about a splice 20between a pair of coextending cable ends 21. The enclosure 14 of FIG. 6molds the resinous composition to form a seal at the end of the shieldon a communication cable 22 so that the insulated conductors 24 of thecable 22 pass through the seal, while the seal prevents the escape ofair under pressure within the shield of the cable 22.

The sheet 16 according to the present invention is formed of a stiffresilient polymer material such as polyvinyl chloride. polyethylene.polyvinyl butyrate. polycarbonate. polystyrene. polyester. ABScopolymers. epoxy. acrylic. or nylon. a preferred material beingpolypropylene in view of the excellent flexing qualities afforded bythin sections thereof. The sheet I6 has a major thickness preferably inthe range of 0.040 to 0.l inch with a preferred thickness of 0.060 inch.One surface 23 of the sheet I6 is grooved to reduce the thickness of thesheet 16 to no greater than 0.030 inch (preferably 0.0l inch) alongnarrow linear intersecting latticed strips 26 (herein called strips).These strips 26 define rectangular and triangular patterns in the sheet16, each of which patterns is comprised of one or more right triangularsheet segment 28. The stiff resilient sheet 16 may be easily severedalong the strips 26 of sheet material at the bases of the grooves as bya shears or pocket knife to cut away unwanted sections of the sheet 16and form a sheet section of a desired configuration for use as anenclosure. Each of the triangular sheet segments 28 is relatively smalland the rectangular and triangular patterns in which they are arrayedafford relatively precise tailoring of a sheet section for a requiredconfiguration to form an enclosure about a cable splice or termination.The sheet section may then be shaped by applying sufficient pressure tothe sheet section so that it will bend along certain of the thin narrowstrips 26 by deformation of the sheet material at the base of thegrooves. The strips 26 will deform without rupturing to allow the sheet16 to be shaped into an enclosure about a splice or termination. Theenclosure may have planar walls and/or walls approximating an arccomprised of a series of adjacent flat sheet portions disposed at anangle to each other by deformation of their connecting strips 26.

The thin narrow intersecting strips 26 of sheet material formed bygrooves in the sheet 16 include a first set 30 of equally spacedparallel longitudinally extending thin narrow strips 26, preferablyspaced at one-half inch intervals. One or more of the strips 26 of thefirst set 30 may be severed to establish the width of a sheet section tobe used as an enclosure. The first set of strips 30 will deform to allowa sheet section to be shaped around a cable termination or splice onfour sides as by shaping a generally cylindrical enclosure. The sheetsection is preferably shaped with the surface 23 in which the groovesare formed as an inner surface to present a smooth outer surface for theenclosure. and so that the maximum deformation of each narrow strip 26may be limited by contact between the walls 32 defining the groove aswill later be explained.

The thin narrow intersecting strips 26 of sheet material also include asecond set 34 of equally spaced parallel strips (spaced preferably on 3inch centers) which intersect the strips 26 of the first set 30 and areperpendicular thereto to define rectangular patterns in the sheet 16.One or more of the strips 26 of the second set 34 may be severed toestablish the length of a sheet section where. as in the enclosuresillustrated in FIGS. 5 and 6. an open end 35 is formed on a cylindricalportion 36 of an enclosure to receive a self-curing liquid resinouscompound. Shaping an enclosure may deform certain strips of the secondset 34 as when triangular sections or projections 38 on a generallycylindrical portion of an enclosure (formed by severing the sheet alongstrips 26 later to be explained) are moved into contact with the surfaceof a cable as has been done on the enclosures illustrated in FIGS. 4, 5,and 6.

The thin narrow intersecting latticed strips 26 of sheet material formedby grooving the sheet 16 also include a third set 40 and a fourth set 41of equally spaced parallel linear thin narrow strips 26. The strips 26of the third and fourth sets 40 and 41 are similarly spaced andintersect each other and the strips of the first set 30 and the secondset 34 at the intersections between the first and second sets 30 and 34.The first, second. third and fourth sets of strips 30, 34, 40. and 41define triangular patterns within and crossing the rectangular patternsdefined by the first and second sets of strips 30 and 34. Intersectingstrips 26 of the third and fourth sets 40 and 4] may be partiallysevered to form the adjacent sheet sections 38 each in the shape of anisosceles triangle having their bases attached at the ends of thecylindrical portions 36 of the closures illustrated in FIGS. 4, 5 and 6.Triangular sheet sections may be cut to different heights andcorresponding widths to accommodate cylindrical sections of variousdiameters. The ends of the triangular sections 38 may be deflectedinwardly to contact and be attached to the jacket of a cable (FIG. 4) asby taping to afford a smooth fitting truncated generally conicaltransition wall 43 between a cylindrical portion 36 of an enclosure andthe periphery of a cable (FIGS. 4, 5 and 6).

The sheet 16 illustrated in FIG. 1 is also grooved in a repetitiveseries of circular patterns around intersections between strips 26 ofthe first and second sets 30 and 34 to form thin narrow annular strips45. These annular strips 45 may be easily severed to afford removal of acorresponding circular section of sheet material and provide an openingthrough which the liquid insulating self-curing resinous compound may beintroduced, as by a funnel, into an enclosure serving as a mold.

The grooves defining the thin narrow strips 26 may have variouscross-sectional shapes, including a U- or V-shape. The grooves may bemachined or hot pressed into the sheet I6. Preferably the grooves aregenerally V-shaped as illustrated in FIG. 2, and are defined by planaredge walls 32 on the sheet segments 28 which converge toward the base ofeach groove which may be slightly radiused. Preferably the edge walls 32are disposed at a angle to each other when the sheet 16 is planar.Contact of the edge walls 32 will limit deformation of the strip 26 attheir base. Thus. the angle between the walls 32 of grooves for at leastthe first set of strips 30 could be decreased as an aid in causing moreequal deformation of the strips 26 to form a generally cylindricalenclosure portion 36 with some loss of versatility for the sheet 16.

The general method for forming enclosures such as those illustrated inFIGS. 4, 5, and 6 will now be explained with particular reference to theenclosure 10 illustrated in FIG. 4.

The workman determines the size and shape of an enclosure to be formed.From a sheet 16 of sufficient size to form the enclosure (or from aseries of sheets joined at their edges as by tape). the workman removesthe unwanted portion of the sheet 16 to form a sheet section of apredetermined configuration for forming the enclosure. This isconveniently done by cutting along certain of the linear strips 26 witha shears or pocket knife. To form an enclosure to fit about the runningsplice 17 illustrated in FIGS. 3 and 4, a sheet section 46 would beformed (as illustrated in FIG. 3) having a rectangular central section47, and a row of the triangular sections 38 having their bases attachedalong each end of the central section 47. The sheet section is thenshaped around the cable to form the enclosure by deforming the sheetmaterial along certain of the narrow strips 26. The sheet section 46illustrated in FIG. 3 will be shaped around the cable 18 into theenclosure 10 illustrated in H0. 4 by applying pressure to the sheetsection 46 to equally deform strips 26 of the first set 30 and shape thegenerally cylindrical enclosure portion 36 from the rectangular centralsection 47. The triangular sections 38 are then pressed toward the cablel8 to deform the strips 26 of the second set 34 which join thetriangular sections 38 to the cylindrical portion 36 and bring the endsof the triangular sections 38 into contact with the cable 18.

The sheet section is attached to itself and to the cable to retain itsshape and location by attaching means which may include taping. Theedges of the rectangular section may be attached by being lapped andtaped together as illustrated in FIGS. 4 and 7. or by being pressed intoopposing tight-fitting grooves on a joining strip 50 as illustrated inFIGS. 6 and 9. As shown in FIG. 4. attaching the edges of therectangular section may also be done by providing longitudinalrectangular sheet portion 52 at the edges of the rectangular sectionwhich may be turned radially outwardly of the cylindrical enclosureportion 36 to serve as lips 52 which may be clipped together as by africtional grooved clip 54 (FIGS. 5 and 8) or serve as guides betweenwhich a funnel may be inserted in a mold with closed ends to add liquidself-curing resinous compound. The triangular sections 38 may beattached by manually pressing them into contact with the cable 18 todeflect their ends until their edges adjoin (left end of FIG. 4 asillustrated). The generally truncated conical enclosure wall 43 thusformed is then wrapped with tape to retain its position and shape (rightend of FIG. 4 as illustrated). Alternatively a tight fitting elasticpreformed cap 55 (FIG. 5) could be pressed over the triangular sectionsto maintain them in position against the cable.

The seal between the ends of the triangular sections 38 and the surfaceof a cable may be facilitated by wrapping a strip of vinyl masticmaterial such as commercially available B sealing tape" about the cableso that the ends of the triangular projections 38 are pressed into thevinyl mastic.

When an enclosure is used for a mold to encapsulate a splice or joint.the wires and connectors may be spaced from the walls of the enclosureby a mat 56 of open porous crush-resistant material having a high voidvolume (FIGS. 4, 5, 6, 7, 8 and 9). The liquid selfcuring resincomposition will fill the void areas and bond to the mat 56 thusinsuring a layer of the cured resin composition between the wires andconnectors and the enclosure wall so that moisture subsequently enteringbetween the enclosure and the encapsulating material cannot contact awire or connector to result in a short circuit or other difficulty.Particularly effective is a randomly woven mat 56 comprising continuousfilaments of cellulose acetate butyrate. having a diameter of preferablybetween 0.0] 3 and 0.022 inch.

While the enclosures illustrated in FIGS. 4, 5 and 6 all have onegenerally cylindrical section with a generally truncated conical sectionon at least one end for joining the cylindrical section to a cable,closures having sections of other configurations such as parallelpipedor wedge-shaped may be easily formed with a sheet 16 according to thepresent invention.

Having thus described the present invention, what is claimed is:

I. An enclosure attached to an electrical cable and extending around asplice or termination in the cable. said enclosure comprising a stiff.resilient, polymeric sheet having latticed grooves on one surface toreduce its thickness and define intersecting sets of spaced parallelnarrow strips connecting segments of the sheet. said sheet being bentalong some of said strips to shape the enclosure. means attaching edgesof the sheet together and means attaching said sheet to the cable.

2. An enclosure according to claim I, further including an electricallyinsulating resinuous composition around the splice within the enclosure.

3. An enclosure according to claim 2, wherein the sheet is ofpolypropylene having a thickness through the segments of between about0.04 to 0.10 inch. and a thickness through the strips of less than about0.03 inch. the spacing between the strips of said first set is about 0.5inch and the spacing between the strips of said second set is about 3inches.

4. An enclosure according to claim 3. wherein said intersecting sets ofstrips include a first longitudinally extending set; a second setperpendicular to and intersecting the first set to define a rectangularpattern; and third and fourth sets oblique to each other. intersectingat every second intersection of the first and second sets. and extendingdiagonally of the rectangular pattern so that the shape of each segmentis right triangular along said one surface.

5. An enclosure according to claim I, wherein said sets of stripsinclude a lonitudinally extending first set. and two additional setshaving strips of equal spacing intersecting each other along the stripsof the first set to form therewith an included angle of less than 45 todefine segments having a triangular shape along said one surface.

6. An enclosure according to claim 1, wherein said grooves are generallyV-shaped. and are defined by generally planar walls converging towardsaid narrow strips.

1. An enclosure attached to an electrical cable and extending around asplice or termination in the cable, said enclosure comprising a stiff,resilient, polymeric sheet having latticed grooves on one surface toreduce its thickness and define intersecting sets of spaced parallelnarrow strips connecting segments of the sheet, said sheet being bentalong some of said strips to shape the enclosure, means attaching edgesof the sheet together and means attaching said sheet to the cable.
 1. Anenclosure attached to an electrical cable and extending around a spliceor termination in the cable, said enclosure comprising a stiff,resilient, polymeric sheet having latticed grooves on one surface toreduce its thickness and define intersecting sets of spaced parallelnarrow strips connecting segments of the sheet, said sheet being bentalong some of said strips to shape the enclosure, means attaching edgesof the sheet together and means attaching said sheet to the cable.
 2. Anenclosure according to claim 1, further including an electricallyinsulating resinuous composition around the splice within the enclosure.3. An enclosure according to claim 2, wherein the sheet is ofpolypropylene having a thickness through the segments of between about0.04 to 0.10 inch, and a thickness through the strips of less than about0.03 inch, the spacing between the strips of said first set is about 0.5inch and the spacing between the strips of said second set is about 3inches.
 4. An enclosure according to claim 3, wherein said intersectingsets of strips include a first longitudinally extending set; a secondset perpendicular to and intersecting the first set to define arectangular pattern; and third and fourth sets oblique to each other,intersecting at every second intersection of the first and second sets,and extending diagonally of the rectangular pattern so that the shape ofeach segment is right triangular along said one surface.
 5. An enclosureaccording to claim 1, wherein said sets of strips include alonitudinally extending first set, and two additional sets having stripsof equal spacing intersecting each other along the strips of the firstset to form therewith an included angle of less than 45* to definesegments having a triangular shape along said one surface.